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Muzzle-to-target “Distance Determinations”!

The investigation of the muzzle-to-target distance must carefully consider several factors.  These include:

  1. Know the weapon - specifically its barrel length and overall operational condition.  It is best to use the actual firearm.
  2. Know the specific ammunition used in the shooting - do not rely on a result that uses “comparable” ammunition, perhaps of a different vintage or even a different manufacturer.  Remember that gunpowed can deteriorate and behave differently given its aging or poor storage conditions.
  3. Know the environmental factors at the time of the incident.
  4. Know the subsequent treatment of the target surfaces.  (Skin gets washed in the emergency room or morgue; powder on clothing may be altered by the “body bag” effect.)  It is best to isolate the target surface at scene and not wait for the morgue (or the pathologists “esitmate”).

Forensic chemical testing of the target that has been isolated and packaged at the scene generates the most reliable muzzle-to-target distance when directly compared to the specific weapon and ammunition.

Two manufacturers of the same type of 45ACP ammunition are shown in the panel at right.

Each was pattern was generated at a distance of 8 inches using the same firearm. Though the diameter is about the same, note that the concentration of powder residues is quite different.  Some ammo is “cleaner buring” than others.

Use the same ammo and same firearm AND know the treatment of the target since the shooting!